MOUBASHER A. H., ABDEL-SATER M. A., SOLIMAN Z. S. M.

Diversity of yeasts and filamentous fungi in mud from hypersaline and freshwater bodies in Egypt.

Abstract

The diversity of yeasts and filamentous fungi in muds from hypersaline alkaline lakes of Wadi ElNatrun and fresh water of the Nile River and Ibrahimia Canal was evaluated. The mean pH of saline water mud was 9.21, but fresh water mud registered 8.07. A total of 193 species (two varieties were distinguished in two of them) belonging to 67 genera were recovered from both muds investigated on DRBC (55 genera, 164 species), DG18 (36 genera, 117 species) and MY50G (23 genera, 76 species) media. From these, 17 species assigned to 12 genera were yeasts and 176 species and 2 varieties assigned to 55 genera were filamentous fungi. The highest numbers of fungal propagules were recovered on DRBC from freshwater mud, while the lowest on MY50G from saline water mud. Yeasts constituted a small proportion of all propagules from the two mud types on all three media, whereas filamentous fungi were the major component. However, freshwater mud samples yielded higher numbers of yeast genera and species using all three media. Candida was common in freshwater mud and rare in saline water mud, while Meyerozyma and Rhodotorula were infrequent in both muds. The remaining yeast species were recovered from freshwater mud only. Aspergillus (46 species) was the most common genus of filamentous fungi encountered in all samples, ranging in frequency from 39.82% to 96.62%; A. terreus, A. flavipes and A. niger dominated in both types of mud. Cladosporium (9 species), Fusarium (8 species), Penicillium (18 species) and Scopulariopsis (7 species) were encountered in both types of mud. Notably, 47 filamentous species were isolated only on the media with lower water activity (DG18, MY50G).